1. Field of the Invention
The present invention relates to novel sulfated metaaminophenols, the intermediate products necessary for their preparation, their use in dyeing keratinous fibers, in particular as coupling agents in dye compositions, and dyeing methods using these compositions.
2. Description of the Prior Art
It is known to dye keratinous fibers, in particular human hair, using dye compositions containing oxidation dye precursors and coupling agents.
Coupling agents, also known as color modifiers, allow the tints obtained with the oxidation dye precursors to be varied.
In the field of dyeing keratinous fibers, in particular human hair, coupling agents are always being sought which, when associated with oxidation dye precursors, will produce a wide range of hair tints with a play of colors and which have satisfactory resistance to light, washing, bad weather, perspiration and other hair treatments.
The applicant has discovered that novel sulfated metaaminophenols as defined below when used as coupling agents in oxidation dye compositions produce a wide range of tints with a play of colors and which are stable and resistant to light, washing, bad weather, perspiration and other hair treatments.
One object of the present invention is therefore the provision of novel sulfated metaaminophenols.
The invention also provides intermediate products used in the preparation of these sulfated metaaminophenols.
Another object of the invention is the use of these metaaminophenols in dyeing keratinous fibers, in particular human hair.
The invention further provides oxidation dye compositions for use in dyeing keratinous fibers, in particular human hair, containing at least one ortho and/or para type oxidation dye precursor and at least these novel sulfated metaaminophenols as coupling agent.
A still further object of the invention is a method of dyeing keratinous fibers, in particular human hair, using such a composition mixed with an oxidizing agent.
Further objects of the invention will become apparent from the description and examples given hereinafter.